Field of the Invention
The present invention relates to wireless communications, and more particularly, to a method and apparatus for enhancing mobility for 3rd generation partnership project (3GPP) long-term evolution (LTE)-wireless local area network (WLAN) aggregation in a wireless communication system.
Related Art
3rd generation partnership project (3GPP) long-term evolution (LTE) is a technology for enabling high-speed packet communications. Many schemes have been proposed for the LTE objective including those that aim to reduce user and provider costs, improve service quality, and expand and improve coverage and system capacity. The 3GPP LTE requires reduced cost per bit, increased service availability, flexible use of a frequency band, a simple structure, an open interface, and adequate power consumption of a terminal as an upper-level requirement.
With the ever increasing demand on mobile broadband services, the usage of unlicensed spectrum in general and wireless local area network (WLAN) in particular remains to be important for 3GPP operators. WLAN was initially deployed to provide opportunistic offload, however with increasing demand for throughput efficient usage of unlicensed spectrum, operator control and reduced WLAN deployment costs become more and more important.
In Rel-13, 3GPP defined LTE-WLAN aggregation (LWA) feature which addresses these requirements. Additionally, institute of electrical and electronics engineers (IEEE) 802.11 specifications continue to evolve. IEEE 802.11 are working on 802.11ax which aims at increasing spectral efficiency in 2.4 and 5 GHz bands, in particular in dense deployments with a theoretical peak throughput up to 9.6 Gbps and 1.6 Gbps under more realistic conditions. In the millimeter wave band of 60 GHz, 802.11ad is a ratified amendment to 802.11 that defines a new physical layer for 802.11 networks and can offer up to 7 Gbps throughputs. 802.11ay is in the process of enhancing 802.11ad and aims at improving mobility, range and providing data rates of at least 20 Gbps. Even though LWA framework has been designed largely agnostic to 802.11 technologies, such increased data rates may require additional optimizations.
The enhanced LWA (eLWA) builds on Rel-13 LWA framework without changes to the LWA architecture and thus supports WLAN nodes deployed and controlled by operators and their partners. One of the objectives of the eLWA is mobility optimization.